Now I'm not saying he's objectively better top
but playstyle wise I feel like he belongs top (I played a lot of him early S4, occasionally do a match or two with him)
It's not that he's bad jungle it just feels off imo. I feel like he is so much more enjoyable in lane, toying with your opponent constantly telling them to improve their skills and messing with them with your clone and such.
For mana issues its hard to say, I used to love taking a couple mana pots after first back so I could be more aggressive, (and sometimes having 1 to start with depending on matchup going longsword +3) I haven't done much of him this season so not much I could say other then hardcore mana management..
As TehNacho said use your Q more than your E, you can really take advantage of the increased AA range to bop someone on the head while their CSing from relative safety, leaving most Es for all ins. If all your trades involve a E-Q-W your going to oom quickly.